High pressure device and method for clean room applications

ABSTRACT

The invention relates to a device creating a hydraulic power stroke for closing a container by means of a rotationally symmetrical lifting system in a very compact form, said device containing a displaceable working piston and a displaceable booster piston which are respectively guided in cylinders. The working piston is hydraulically driven and the booster piston is pneumatically driven, both pistons being in direct axial active communication by means of a fluid located in a cavity between the bottom surface of the working cylinder and the front side of the booster piston. The front side of the working piston at least partially forms the closure of the container or is rigidly connected to the closing element of the container.

The invention relates to a device for the closure of a vessel and/orforming and pressing semi-finished products by means of arotation-symmetric reciprocating piston mechanism of extremely compactdesign, which includes a hydraulic piston and an intensifier piston,each of which run in cylinders. The hydraulic piston is driven usingwater, the intensifier piston pneumatically, the two forming a directaxial functional unit via a fluid located in a space between the lowerface of the hydraulic cylinder and the upper face of the intensifierpiston. The upper face of the hydraulic piston forms at least partiallythe closure part of the vessel or it is rigidly connected to a closureelement for the vessel, or the upper side of the hydraulic piston formsthe tools or is rigidly connected to said tools.

The spectre of products developed by the semiconductor manufacturing,opto-electronic and other industries is constantly expanding and thesaid products permit to realise the central functions with the aid or onthe basis of micro or nano-structures. The said structures also reactextremely sensitive to minor impurities during the production phase.Hence, ever more stringent requirements are specified for the admissibleemission rates of components used in the said ambience. The cleaningsteps required for nano-structured surfaces cannot be carried out byconventional cleaning agents or they are hardly feasible. For some timesupercritical fluids have been used on a large scale as they enhance thewetting effects and cleaning results. These operations necessitateprocess pressures which range from 150 to more than 300 bars and whichconsequently require special equipment. So far high-pressure equipmentwith adequate mechanical properties was not directly suitable for cleanroom operations or it was even unsuitable for such applications. Thisinvention describes a high-pressure unit of a very compact design whichis suited for clean-room applications at high pressure levels and whichonly produces minor emissions when alternating load cycles take place athigh pressure level.

Reciprocating piston mechanisms for pressures of >150 bar are in broadand diverse technical and commercial use and have been adequatelydescribed in patent-specific and general technical literature.

Reciprocating piston mechanisms which include, inter alia, hydraulicpistons and intensifier pistons, with the upper face of the intensifierpiston acting axially on an operating fluid, which is enclosed in thecylinder chamber below the lower face of the hydraulic piston and causesthe working stroke or maximum pressure on the hydraulic piston, are alsoknown from the relevant literature.

Specifications DE 100 26 616 A1 and WO 01/69088 A1 describe theabove-mentioned reciprocating piston mechanisms in which the operatingfluid of the hydraulic piston and that of the pressure intensifier isidentical. JP 55126103 discloses such a reciprocating piston mechanism,which is equipped with an additional vessel in which displaced hydraulicfluid is temporarily stored. WO 01/69088 A1 also describes a returnfunction of the hydraulic piston, the function being executed in such away that the plunger of the hydraulic piston travels in a spring, whichis clamped in the course of the piston stroke between the cylinder headand the bottom of the piston. The spring relaxes and returns thehydraulic piston to its initial position when the action of force on thepiston ceases.

Also known from and adequately described in the relevant literature arereciprocating piston mechanisms which include for the hydraulic pistonan operating fluid different to the operating fluid for the intensifierpiston. The hydropneumatic devices described in Specifications JP09280202 and DE 199 46 678 A1 may be mentioned here as examples of suchcombined mechanisms.

Liquids and gases are used as the operating fluids, mainly water beingused for pressures of up to around 160 bar, and hydraulic fluids above160 bar. Inert gases and air are the most commonly used gaseousoperating fluids. Hydraulic fluid exhibits important beneficialcharacteristics in terms, inter alia, of lubrication of slidingsurfaces, low compressibility and high temperature stability.

Detrimental effects which cannot be completely eliminated frompiston-based devices include, inter alia, material erosion and operatingfluid leakage. Friction- and pressure-induced material erosion, such asabrasion, evaporation and liquefaction, for example, occur to a limitedextent even on the parent material itself and, in particular, in and onthe sealing system. Material erosion in reciprocating piston mechanismsis a function essentially of the surface quality of the sliding surfacesand the manufacturing tolerances of the components, of the sealingmaterial and the radial contact pressure of the sealing member, and alsoof temperature.

Leakage of the operating fluid, certain quantities of which areentrained at every piston stroke, is functionally dependent on, interalia, quality of surfaces, viscosity, hydrostatic pressure in thecylinder chamber and also on the sealing system and sealing memberdesign and the radial contact pressure of the sealing members andsealing system.

High working pressures necessitate adequate lubrication of the surfacesfacing each other and running against one another, resulting incorresponding leakage quantities. This effect can be minimized by meansof suitable sealing systems and a high-quality surface treatment. Thepotentials for increasing contact pressure in order to suppress leakageare however restricted by the fact that the degradation and erosion ofthe sealing material increases as pressure rises, with the consequencesof emissions and, subsequently, greater leakage quantities. In addition,the limits of mechanical load-bearing capacity and economic operationare reached.

Impurities resulting from material erosion and leakage from theabove-mentioned sources are of extreme disadvantage in the productionzone, particularly in the case of cleanroom processes. Clean-roomclasses are defined, for example, in DIN 2083 and Federal Standard 209D.Emissions of any type whatsoever have a direct influence on the qualityof the products of these processes and a high level of equipment andorganizational input is applied to minimize such emissions, inevitablywith high associated costs. Of particular seriousness and disadvantageis contamination with oil mists, since oil-containing emissions are inmany cases chemically active and can be removed again only usingsolvent-containing agents which, for their part, are not desirable incleanrooms and can, indeed, be extremely disadvantageous there.

It is known that fluid-hydraulic reciprocating piston mechanisms used incleanrooms are somewhat problematic and have to be rendered suitable forcleanroom applications by means of appropriate exhausting systems (SWISSContamination Control 5 (1992) No. 5, p. 8 ff.). Oil depositionsoccurred on the semi-finished product when a pressing die was used forthe production of CD blanks, for example. Investigations revealed thatthe hydraulic fluid was the source of this impurities. The necessarysuitability for cleanroom use was restored by fitting sealed sleeves tothe die's connecting rods and by means of exhausting of the presshousing and of the air from the sleeves.

A further technical article discloses a pneumatic cylinder with nopiston-rod (Dr.-Ing. E. Fritz; Paper for the 1^(st) Int. ForumFluidtechnisches Kolloquium, Volume 2, pp. 283 ff.). Suitability forcleanroom service was achieved by generating a partial vacuum in thespace between the covering strip and the sealing strip. Vacuumconnections were fitted to the cylinder tube for this purpose, and theemissions were routed away.

A disadvantage of the above-mentioned reciprocating piston mechanismsincorporating an exhausting system is the fact that additional systemsare necessary for the assurance of minimum particle concentrations andthat these systems must be installed and continuously operated.

Spatial separation is implemented in the case of more complex productionsystems, in which components with cleanroom capability are usedsimultaneously with less suitable components. The equipment not suitablefor cleanroom service is accommodated in so-called “maintenance zones”,while the cleanroom-capable equipment is housed in so-called “whiterooms”. Such solutions necessitate complex and expensive fluid-locksystems and organizational precautions in order to ensure the exclusionof impurities from the “maintenance zone”.

U.S. Pat. No. 6,067,728 disclosed a device and a process for the dryingof wafers using supercritical CO₂, a pneumatico-mechanical closuredevice being incorporated. The closure of the vessel plug isaccomplished by means of a pneumatic piston and lever device,pre-pressurization being achieved by means of this arrangement. The plugis locked in place by means of clips. After pneumatico-mechanicalclosure of the process room, one or more static clips are positionedsymmetrically on the edge of the cover. These closure clips are pushedmechanically over the edge of the vessel leakage and the vessel base andprovide the tightness of the vessel during the process, as internalpressure rises.

A disadvantage of the above-mentioned invention are the many movingparts, which may be regarded as critical in terms of emissions, andwhich severely limit the number of reciprocating strokes and/or numberof possible process cycles per unit of time, as a result of thenecessary movements. In addition, the many operations required alsonecessitate a complex control device.

The objective of the invention is to avoid additional exhaust andprotective systems and/or specific partition of the available space bymeans of technical solutions implemented on the reciprocating pistonitself. In addition, types which fulfill the necessities of safe anddependable operation with the lowest possible number of movements andlowest possible number of moving parts are to be achieved.

The present invention provides for a solution to this problem inaccordance with the main claim by means of a device for closure of aprocess vessel using a reciprocating cylinder, characterized in that thereciprocating cylinder consists of not less than one water-hydraulicallydriven piston which, via a fluid, forms a direct functional unit inaxial direction with a pneumatically driven intensifier piston, theupper face of the hydraulic piston taking the form of an integralcomponent of a vessel and constituting the vessel's closure element.

In a further embodiment of the invention, at least a part of the slidingsurfaces exhibits a surface structure support ratio of >60%.

In another embodiment of the invention, at least a part of the slidingsurfaces is hardened.

In a further process embodiment, a fluid other than water is used in thecylinder chamber, this fluid preferably being a readily volatile fluid,or a gas being used as the operating fluid. It is advantageous tooperate the hydro-pneumatic piston using compressed air or another gasor mixture of gases.

In a further advantageous variant of the process arrangement, resettingof the hydraulic piston by the fluid enclosed in the cylinder chamberdirectly accomplishes resetting of the intensifier piston, since thefluid acts on the upper face of the intensifier piston so that itreturns to its starting position.

A developed variant of the process arrangement includes synchronizationof the reciprocating and closure unit with the process cycle takingplace in the vessel.

In a further advantageous embodiment of the process, a pressure of >180bar is reached at regular intervals on the upper face of the hydraulicpiston and/or in the vessel, the pressure in said face regularly beingequal to or greater than the pressure in the vessel.

The invention also includes an application of the device for processesin which at least one supercritical gas is used in the vessel.

The device and process in accordance with the invention can therefore beadvantageously used for processes which take place directly orindirectly in clean-room and/or in similar laboratory or workingfacilities.

The invention also includes an application of the device and/or processfor manufacturing processes directly or indirectly associated with atleast one application, production method or process in the semiconductorand/or wafer production industry, the optics industry, thepharmaceuticals industry and/or medical and medicinal productsindustries.

In a further advantageous embodiment of the device, the upper face ofthe hydraulic piston takes the form of a pressing die or is rigidlyconnected to a pressing die, the latter essentially moving also axiallyrelative to the hydraulic piston. A pressing process using theabove-mentioned pressing die, which would be utilized for pressingoperations, such as forming, gluing/adhesive bonding or for input ofmaterials under clean-room conditions, is thus covered by the invention.

FIGS. 1 to 4 show a longitudinal sectional view of the device.

FIG. 1: Reciprocating piston mechanism

FIG. 2: Reciprocating piston mechanism and valves in the startingposition of the reciprocating operation (“vessel open”)

FIG. 3: Reciprocating piston mechanism and valves at the end of thepre-pressurising phase and pressure intensifier in starting position(“vessel closed”)

FIG. 4: Reciprocating piston mechanism and valves during the high-loadphase, pressure intensifier in end position (“vessel locked”)

The present invention is described below in more detail using furtherexplanatory notes, examples and FIGS. 1 to 4. FIG. 1 shows thehydropneumatic reciprocating piston and closure unit in accordance withthe invention, in which a water-hydraulic hydraulic piston (1) formsaxially a direct functional unit with a pneumatic intensifier piston(2), via a fluid, which is located in cylinder chamber (3). The upperend face (18) of the pressure intensifier acts on the above-mentionedfluid and is arranged parallel to the bottom surface (19) of thehydraulic cylinder. The upper end of hydraulic piston 1 additionallyforms the closure of pressure vessel (9) and is in the present versionthe bottom plate of the vessel (9). Sliding surfaces (13-16) of thereciprocating piston and closure unit in accordance with the inventionare designed in such a way that they have a high support ratio and/orhigh hardness.

FIGS. 2 to 4 show in schematic form the device and the process as theyhave already been implemented in a test facility on an industrial 1:1scale. This test facility has been operated continuously at full loadfor a period of ten weeks. The pilot pressure in cylinder chamber (3)was achieved from a large water-piping system with no additionalpressure boosting and was around 6 bar. N₂ from a battery of pressurecylinders was used as the pneumatic operating fluid for cylinder chamber(4), the pressure of 25 bar being achieved by means of correspondingpressure reduction. This test apparatus and this process achieved withina period of ten consecutive weeks approximately 100000 load cycles at aworking pressure of 1 to approx. 260 bar on the upper face (17) ofhydraulic piston (1). In the test apparatus, the upper face of hydraulicpiston 1 was moved up against a yoke and held there for approx. 3seconds in every cycle.

With respect to preparation of the material sliding surfaces, it becameapparent that the sliding surfaces need to have a support ratio of >60%in order to avoid galling of the sliding surfaces and that hardening ofthese surfaces is an advantage. Austenitic materials were used; thisdevice is not restricted to this group of materials, however.

The methods for achievement of high support ratios are adequatelydescribed in the relevant literature. Applicable processes include, forexample, honing, lapping and tumbling. Hardening of the surfacespretreated in this way can be achieved by means of plasma-nitriding,kolsterizing or hard chromium plating, it is also state-of-the-art andis commercially available from specialized companies.

This also covers a process for operation of the device in accordancewith the invention, in which a hydraulic piston 1 is moved to the loadposition by means of hydrostatic water pressure (FIG. 3). Valve (21) isof a type that permits to close bores (10 and 11). Positioning ofintensifier valve (22) causes pressure to be applied to the lower face(20) of the intensifier piston, thus moving this piston. The ultimatepressure in the closed cylinder chamber (3) rises in accordance with theratio of the surfaces of lower face (20) to upper face (18), and thenecessary contact pressure of the upper face (18) on to vessel (9) isgenerated on sealing member (23) via hydraulic piston (1).

After completion of the load cycle, intensifier valve (22) is opened andcylinder chamber (4) depressurized, the operating fluid of pressureintensifier (2) being released into the atmosphere. Hydraulic valve (21)is then set in such a way that cylinder chamber (5) iswater-hydraulically pressurized, with the result that hydraulic piston(1) moves to its starting position synchronously with intensifier piston(2).

The cycle starts again from the “vessel open” position (FIG. 2), withpositioning of hydraulic valve (21) causing operating fluid to be fedvia bore (10) into cylinder chamber (3).

The function of pressure intensifier (2) depends on the return motion ofhydraulic piston (1), which constitutes a particularly advantage withreference to the current state of the art. This link eliminates the needfor separate resetting of intensifier piston (2) and for precise controlof the valve cycles. There is also advantage in that the valve positionis largely uncoupled at the start of the load cycle. For initialpressurization of cylinder chamber (3), intensifier valve (22) canremain in the position which it attained at the end of the load cycle(“locked vessel” position; see FIG. 4). Compared to known devices,synchronization of piston resetting, uncoupled valve positions at thestart of the load cycle and extremely short stroke lengths mean that thedevice does not require a sophisticated control unit and is particularlysuitable for rapid load changes and high pressures.

Compared to known devices, mechanical damage is largely prevented by thefact that indirect transmission of force is achieved from theintensifier piston to the hydraulic piston via the fluid bridge incylinder chamber (3). This is ensured by the fact that in the “Vesselclosed” end position, cylinder chambers (5 and 6) are not completelyemptied and that the surfaces of the pistons therefore never come intodirect axial contact with the cylinder walls in the direction of thestroke. This also applies to the upper face of the intensifier pistonrelative to the lower face of the hydraulic piston.

A particular advantage compared to known reciprocating piston mechanismsis the gentle operation of the hydraulically operated piston (1), whichresults in only minor loads being exerted on sealing members (25 and27). In the end position of hydraulic piston (1) with onset of ultimateforce via pressure intensifier (2), there is no further motion relativeto one another between the sealing surface and piston walls (13 and 15).Potential emissions from sealing members (24 and 26) are retained incylinder chambers (3, 4 and 6) and expelled via bores (10, 12 and 24)during the normal working cycle. No additional partial vacuum isnecessary, and a significant advantage is therefore achieved compared tothe current state of the art.

KEY TO DIAGRAMS

-   1 Hydraulic piston-   2 Intensifier piston-   3 Intermediate space-   4 Cylinder chamber-   5 Cylinder chamber-   6 Cylinder chamber-   7 Hydraulic cylinder-   8 Intensifier cylinder-   9 Pressure vessel-   10 Bore-   11 Bore-   12 Bore-   13 Sliding surface-   14 Sliding surface-   15 Sliding surface-   16 Sliding surface-   17 Upper face of the hydraulic piston-   18 Upper face of the intensifier piston-   19 Lower face of the hydraulic piston-   20 Lower face of the intensifier piston-   21 Hydraulic valve-   22 Intensifier valve-   23 Sealing member-   24 Sealing member-   25 Sealing member-   26 Sealing member-   27 Sealing member

1-21. (canceled)
 22. A reciprocating piston device for the closure of avessel and consisting of at least one base element and one closureelement, said system encompassing at least one movable piston (1) withone hydraulic cylinder each (7), and at least one movable intensifierpiston (2) also combined with one intensifier cylinder each (8), all ofwhich are rotationally symmetrical, hydraulic piston (1) and itshydraulic cylinder (7) and intensifier piston (2) and its intensifiercylinder (8) each being arranged along an axis of rotation and hydraulicpiston (1) featuring on the piston end located in the hydraulic cylinder(7) at least one circumferential reinforcement running radially on itsouter surface, with the result that the internal space between thehydraulic cylinder (7) and the hydraulic piston (1) is divided into notless than two subsidiary spaces (3) and (5), and not less than one bore(10) and (11) in hydraulic cylinder (7) leading to each of thesesubsidiary spaces, the cylinder (1) being driven water-hydraulically andthe intensifier piston (2) pneumatically, wherein hydraulic piston (1)and intensifier piston (2) are incorporated into a direct axial functionin relation to the axis of rotation, via the fluid located in space (3)between lower face (19) of piston (1) and upper face (18) of intensifierpiston (2), the upper face of hydraulic piston (1) forming at least partof the closure of vessel (9) or being rigidly connected to the closurepart of vessel (9), and the said closure part essentially moves alongthe axis of rotation in relation to hydraulic piston (2), and vessel (9)is arranged opposite the upper face of hydraulic piston (1), and atleast one of the sliding surfaces (13 to 16) located on the internalsurfaces of the cylinders and on the piston surfaces in the zones inwhich the cylinder and piston surfaces are located opposed to oneanother and in contact and move relative to one another parallel to theaxis of rotation, shows a support ratio of >60%, said ratio representingthe proportion of “peaks” to the “valleys” of the surface structure, andthe reciprocating piston system is open with regard to the feed anddischarge of the operating fluid.
 23. A device according to claim 22,wherein at least one of the sliding surfaces located on the internalsurfaces of the cylinder and the piston surfaces in the zones in whichthe cylinder and piston surfaces are located opposed to one another andare in contact and are moved relative to one another parallel to theaxis of rotation is hardened.
 24. A process for operation of the deviceaccording to claim 22, wherein the position of a hydraulic valve (21),which controls the feed and discharge of cylinder chambers (3 and 5) ofhydraulic cylinder (7), causes feeding of fluid to lower face (19) ofhydraulic piston (1) by feeding, via not less than one delivery line andbores (10), of fluid into space (3) between upper face (18) ofintensifier piston (2) and lower face (19) of hydraulic piston (1), andthus moves the hydraulic piston from the “vessel open” starting positionto the “vessel closed” pre-pressurizing position and closing vessel (9),hydraulic valve (21) then moving in such a way that all routes toborings (10 and 11) assigned to hydraulic cylinder (7) of hydraulicpiston (1) are closed and the subsequent positioning of intensifiervalve (22), which controls the feed and discharge of the cylinderchambers (4) and (6) of intensifier piston, causing fluid to be appliedto lower face (20) of intensifier piston (2) by the feeding, via notless than one delivery line and bores (12) in the cylinder wall, offluid into cylinder chamber (4) below lower face (20) of intensifierpiston (2) and intensifier piston (2) therefore moving to the “vessellocked” end position and the said position being maintained for anyperiod of time required, intensifier valve (22) then being opened andthe fluid in cylinder chamber (4) below lower face (20) of intensifierpiston (2) being depressurized and subsequently hydraulic valve (21)being positioned in such a way that via at least one delivery line andbore (11) fluid is fed into upper space (5) in hydraulic cylinder (7) ofhydraulic piston (1) and the pressure acting on the essentially annularand essentially parallel surface of the circumferential pistonreinforcement located opposite the lower face (19) of hydraulic cylinder(1) in such a way that hydraulic piston (1) moves to its “vessel open”starting position, the fluid, which is enclosed in the space underneathhydraulic piston (1), thereby acting on upper face (18) of intensifierpiston (2) and moving this, too, into its starting position.
 25. Adevice according to claim 22, wherein a readily volatile fluid from thegroup formed by ethanol, methanol, isopropanol and similar substances ormixtures, is used as the fluid in the spaces formed by hydrauliccylinder (7) of hydraulic piston (1), or that a gas consistingessentially of CO₂, oxygen, nitrogen, a noble gas or mixtures thereof isused as the fluid in the said spaces.
 26. A device in according to claim22, wherein a readily volatile fluid from the group formed by ethanol,methanol, isopropanol and similar substances or mixtures thereof, isused as the fluid in spaces (4) and (6) formed by intensifier cylinder(8) of intensifier piston (2) or that a gas consisting essentially ofCO₂, oxygen, nitrogen, a noble gas or mixtures thereof is used as thefluid in the said spaces.
 27. A device according to claim 22, wherein aworking pressure of >180 bar is regularly reached on upper face (17) ofhydraulic piston (1).
 28. A device according to claim 22, wherein apressure of >180 bar is regularly reached in vessel (9).
 29. Areciprocating piston device for pressing or forming of at least onesemi-finished product, consisting of not less than one hydraulic piston(1) each with a hydraulic cylinder (7), and not less than one movingintensifier piston (2) each with an intensifier cylinder (8), allrotationally symmetrical, hydraulic piston (1) and its hydrauliccylinder (7) and intensifier piston (2) and its intensifier cylinder (8)each being arranged along an axis of rotation, and the hydraulic pistonend located in the hydraulic cylinder having not less than onecircumferential reinforcement running radially on the external surface,such that the internal space between hydraulic cylinder (7) andhydraulic piston (1) is divided into not less than two subsidiarychambers (3) and (5), and at least one bore (10) and (11) in hydrauliccylinder (7) leading to each of these subsidiary chambers (3) and (5),hydraulic piston (1) being actuated water-hydraulically and intensifierpiston (2) pneumatically, characterized in that hydraulic piston (I) andintensifier piston (2) form a direct axial functional unit with oneanother relative to the axis of rotation, with the aid of a fluid whichis located in a space (3) between lower face (19) of hydraulic cylinder(1) and upper face (18) of intensifier piston (2), the upper face ofhydraulic piston (I) at least partially forming the pressing or formingtool or being rigidly connected to a pressing or forming tool and thispressing or forming tool essentially moving along the axis of rotationrelative to hydraulic piston (1) and the semifinished product beinglocated opposite the upper face (17) of hydraulic piston (1), at leastone of the sliding surfaces (13 to 16) located on the internal surfacesof the cylinders and on the piston surfaces in the zones in which thecylinder and piston surfaces are located opposed to one another and incontact and move relative to one another parallel to the axis ofrotation, shows a support ratio of >60%, said ratio representing theproportion of elevations (“peaks”) to the depressions (“valleys”) of thesurface structure.
 30. The device according to claim 29, wherein atleast one of the sliding surfaces located on the internal cylindersurfaces and on the piston surfaces in the zones in which the cylinderand piston surfaces are located opposite one another and are in contactand moved parallel to the axis of rotation, is hardened.
 31. The deviceaccording to claim 29, wherein the positioning of a hydraulic valve (21)which controls the feed and discharge of cylinder chambers (3) and (5)of hydraulic cylinder (7) causes feeding of fluid to the lower face (19)of hydraulic piston (I), by feeding of fluid via not less than onedelivery line and bore (10) into the space between upper face (18) ofintensifier piston (2) and lower face (19) of hydraulic piston (I) and,thus, movement of the hydraulic piston from its “no product contact”starting position into its “product contact” pre-pressurizing position,valve (21) subsequently being moved in such a way that all paths tobores (10) and (11) assigned to hydraulic cylinder (7) of hydraulicpiston (1) are closed and by subsequent setting of intensifier valve(22), which controls the feed and discharge of cylinder chambers (4) and(6) of intensifier piston (2), feeding of fluid to lower face (20) ofintensifier piston (2) occurs, by feeding of fluid via not less than onedelivery line and bore (12) in the cylinder wall into cylinder chamber(4) below lower face (20) of intensifier piston (2), and thereforeintensifier piston (2) to be moved to its “pressed product” end positionand this “pressed product” position to be retained for any period oftime required, intensifier valve (22) then being opened and the fluid incylinder chamber (4) below lower face (20) of intensifier piston (2)being depressurized, and hydraulic valve (21) then being positioned insuch a way that fluid is fed via not less than one delivery line andbore (11) to upper space (5) of hydraulic cylinder (7) of hydraulicpiston (1) and the pressure acting on the essentially annular andessentially parallel surface area of the circumferential reinforcementlocated opposite the lower face (19) of hydraulic cylinder (1) in such away that hydraulic piston (I) moves into its “no product contact”starting position, the fluid enclosed in space (3) below hydraulicpiston (I) acting on upper face (18) of intensifier piston (2) andmoving this, too, into its starting position.
 32. The device accordingto claim 29, wherein a readily volatile fluid taken from the groupformed by ethanol, methanol, isopropanol and similar substances ormixtures thereof is used as the fluid in the chamber (3) and (5) formedby hydraulic cylinder (7) and its hydraulic piston (I) or that a gasconsisting essentially of CO₂, oxygen, nitrogen, a noble gas or mixturesthereof is used as the fluid in the said chambers.
 33. The deviceaccording to claim 29, wherein a readily volatile fluid taken from thegroup formed by ethanol, methanol, isopropanol and similar substances ormixtures thereof is used as the fluid in chambers (4) and (6) formed byintensifier cylinder (8) and its intensifier piston (2) or that a gasconsisting essentially of CO₂, oxygen, nitrogen, a noble gas or mixturesthereof is used as the fluid in the said chambers.
 34. The deviceaccording to claim 29, wherein a working pressure of >180 bar isregularly achieved on the upper face (17) of hydraulic piston (1).